Characterization of the gut microbiota in polycystic ovary syndrome with dyslipidemia

BACKGROUND

Polycystic ovary syndrome (PCOS) is an endocrinopathy in childbearing-age females which can cause many complications, such as diabetes, obesity, and dyslipidemia. The metabolic disorders in patients with PCOS were linked to gut microbial dysbiosis. However, the correlation between the gut microbial community and dyslipidemia in PCOS remains unillustrated. Our study elucidated the different gut microbiota in patients with PCOS and dyslipidemia (PCOS.D) compared to those with only PCOS and healthy women.

RESULTS

In total, 18 patients with PCOS, 16 healthy females, and 18 patients with PCOS.D were enrolled. The 16 S rRNA sequencing in V3-V4 region was utilized for identifying the gut microbiota, which analyzes species annotation, community diversity, and community functions. Our results showed that the β diversity of gut microbiota did not differ significantly among the three groups. Regarding gut microbiota dysbiosis, patients with PCOS showed a decreased abundance of Proteobacteria, and patients with PCOS.D showed an increased abundance of Bacteroidota compared to other groups. With respect to the gut microbial imbalance at genus level, the PCOS.D group showed a higher abundance of Clostridium_sensu_stricto_1 compared to other two groups. Furthermore, the abundances of Faecalibacterium and Holdemanella were lower in the PCOS.D than those in the PCOS group. Several genera, including Faecalibacterium and Holdemanella, were negatively correlated with the lipid profiles. Pseudomonas was negatively correlated with luteinizing hormone levels. Using PICRUSt analysis, the gut microbiota community functions suggested that certain metabolic pathways (e.g., amino acids, glycolysis, and lipid) were altered in PCOS.D patients as compared to those in PCOS patients.

CONCLUSIONS

The gut microbiota characterizations in patients with PCOS.D differ from those in patients with PCOS and controls, and those might also be related to clinical parameters. This may have the potential to become an alternative therapy to regulate the clinical lipid levels of patients with PCOS in the future.

Ligilactobacillus Salivarius LCK11 Prevents Obesity by Promoting PYY Secretion to Inhibit Appetite and Regulating Gut Microbiota in C57BL/6J Mice

SCOPE

Obesity is a common disease worldwide and there is an urgent need for strategies to preventing obesity.

METHODS AND RESULTS

The anti-obesity effect and mechanism of Ligilactobacillus salivarius LCK11 (LCK11) is studied using a C57BL/6J male mouse model in which obesity is induced by a high-fat diet (HFD). Results show that LCK11 can prevent HFD-induced obesity, reflected as inhibited body weight gain, abdominal and liver fat accumulation and dyslipidemia. Analysis of its mechanism shows that on the one hand, LCK11 can inhibit food intake through significantly improving the transcriptional and translational levels of peptide YY (PYY) in the rectum, in addition to the eventual serum PYY level; this is attributed to the activation of the toll-like receptor 2/nuclear factor-κB signaling pathway in enteroendocrine L cells by the peptidoglycan of LCK11. On the other hand, LCK11 supplementation effectively reduces the Firmicutes/Bacteroidetes ratio and shifts the overall structure of the HFD-disrupted gut microbiota toward that of mice fed on a low-fat diet; this also contributes to preventing obesity.

CONCLUSION

LCK11 shows the potential to be used as a novel probiotic for preventing obesity by both promoting PYY secretion to inhibit food intake and regulating gut microbiota.

Intestinal Dysbiosis Correlates With Sirolimus-induced Metabolic Disorders in Mice

BACKGROUND

Long-time use of pharmacological immunosuppressive agents frequently leads to metabolic disorders. Most studies have focused on islet toxicity leading to posttransplantation diabetes mellitus. In contrast, the link between intestinal dysbiosis and immunosuppressive drug-induced metabolic disorders remains unclear.

METHODS

We established a mouse model of metabolic abnormality via sirolimus treatment. Fecal microbiota was examined using 16S rRNA gene MiSeq sequencing. Intestinal barrier function was assessed using fluorescein isothiocyanate-dextran assay and mucus immunostaining. Systemic inflammation was determined using a multiplexed fluorescent bead-based immunoassay.

RESULTS

Sirolimus induced dyslipidemia and glucose intolerance in mice in a dose-dependent manner. Interestingly, the clinical-mimicking dose of sirolimus altered the intestinal microbiota community, which was characterized by the enrichment of Proteobacteria, depletion of Akkermansia, and potential function shifts to those involved in lipid metabolism and the immune system. In addition, the clinical-mimicking dose of sirolimus reduced the thickness of the intestinal mucosal layer, increased the intestinal permeability, and enriched the circulating pro-inflammatory factors, including interleukin (IL)-12, IL-6, monocyte chemotactic protein 1, granulocyte-macrophage colony stimulating factor, and IL-1β. Our results showed a close association between intestinal dysbiosis, intestinal barrier failure, systemic inflammation, and metabolic disorders. Furthermore, we demonstrated that oral intervention in the gut microbiota by Lactobacillus rhamnosus HN001 protected against intestinal dysbiosis, especially by depleting the lipopolysaccharide-producing Proteobacteria, and attenuated the sirolimus-induced systemic inflammation, dyslipidemia, and insulin resistance.

CONCLUSIONS

Our study demonstrated a potentially causative role of intestinal dysbiosis in sirolimus-induced metabolic disorders, which will provide a novel therapeutic target for transplant recipients.

The effect of probiotic fermented milk products on blood lipid concentrations: A systematic review and meta-analysis of randomized controlled trials

AIM

Fermented milk products are suggested as a supplementary therapy to help reduce blood lipid levels. However, the results of clinical studies are conflicting.

DATA SYNTHESIS

This study systematically reviewed 39 randomized controlled trials (n = 2237 participants) to investigate the effect of probiotic fermented milk products on blood lipids. A meta-analysis was performed using random effects models, with weighted mean differences (WMDs) and 95% confidence interval (CI). Statistically significant reductions in blood low-density lipoprotein cholesterol (LDL-C) (WMD: -7.34 mg/dL, 95% CI: from -10.04 to -4.65, and P < 0.001) and total cholesterol (TC) concentrations (WMD: -8.30 mg/dL, 95% CI: from -11.42 to -5.18, and P < 0.001) were observed. No statistically significant effect of probiotic fermented milk was observed on blood high-density lipoprotein cholesterol (HDL-C) and triacylglycerol (TAG) levels. The effect on TC and LDL-C level was more pronounced in men, and a greater reduction in TAG was observed in trials with longer interventions (≥8 weeks) as compared to their counterparts.

CONCLUSIONS

Available evidence suggests that probiotic fermented milk products may help to reduce serum TC and LDL-C cholesterol levels, particularly in men and when they are consumed for ≥8 weeks.

Bilberry Anthocyanins Ameliorate NAFLD by Improving Dyslipidemia and Gut Microbiome Dysbiosis

Non-alcoholic fatty liver disease (NAFLD) is a manifestation of metabolic syndrome closely linked to dyslipidemia and gut microbiome dysbiosis. Bilberry anthocyanins (BA) have been reported to have preventive effects against metabolic syndrome. This study aimed to investigate the protective effects and mechanisms of BA in a Western diet (WD)-induced mouse model. The results revealed that supplementation with BA attenuated the serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), low-density lipoprotein cholesterol (LDL-c), fat content in liver, 2-thiobarbituric acid reactive substances (TBARS) and α-smooth muscle actin (α-SMA) caused by WD. Furthermore, gut microbiota characterized by 16S rRNA sequencing revealed that BA reduced remarkably the ratio of Firmicutes/Bacteroidetes (F/B) and modified gut microbiome. In particular, BA increased the relative abundance of g_Akkermansia and g_Parabacteroides. Taken together, our data demonstrated that BA might ameliorate WD-induced NAFLD by attenuating dyslipidemia and gut microbiome dysbiosis.

Gut microbiota health closely associates with PCB153-derived risk of host diseases

Although the production and use of PCB153 have been banned globally, PCB153 pollution remains because of its persistence and long half-life in the environment. There is ongoing evidence that exposure to PCB153 may influence gut microbiota health and increase the risk of host health. It is needed to illuminate whether there are associations between gut microbiota dysregulation and PCB153-induced host diseases. Importantly, it is urgently needed to find specific strains as biomarkers to monitor PCB153 pollution and associated disorders. The work aims to investigate the change of gut microbiota composition, structure and diversity and various host physiological indexes, to ravel the chain causality of PCB153, gut microbiota health and host health, and to find potential gut microbiota markers for PCB153 pollution. Here, adult female mice were administrated with PCB153. Obtained results indicated that PCB153 led to gut microbiota health deterioration. PCB153 exposure also induced obesity, hepatic lipid accumulation, abdominal adipose tissue depots and dyslipidemia in mice. Furthermore, specific gut microbiota significantly correlated with the host health indexes. This work provides support for the relationship between gut microbiota aberrance derived from PCB153 and risk of host health, and offers some indications of possible indicative functions of gut microbiota on PCB153 pollution.

Meat Protein in High-Fat Diet Induces Adipogensis and Dyslipidemia by Altering Gut Microbiota and Endocannabinoid Dysregulation in the Adipose Tissue of Mice

Endocannabinoids modulate insulin and adipokine expression in adipocytes through cannabinoid receptors and their levels are elevated during hyperglycemia and obesity, but little is known about how diets affect them. We assessed the effects of dietary casein, chicken, beef, and pork proteins in a high-fat diet mode, on endocannabinoids, adipogenesis, and biomarkers associated with dyslipemdia. A high-fat beef or chicken diet upregulated cannabinoid 1 receptor, N-acyl phosphatidylethanolamine-selective phospholipase-D and diacylglycerol lipase α in adipose tissue and reduced the immunoreactivity of mitochondrial uncoupling protein 1 in brown adipose tissue. In addition, the high-fat diets with beef and chicken protein had a significant impact on adipocyte differentiation and mitochondrial biogenesis in obese mice. A 16S rRNA gene sequencing indicated that high-fat diets, regardless of the protein source, significantly enhanced the ratio of Firmicutes to Bacteroidetes in colon. Meat proteins in a high-fat diet significantly decreased the relative abundances of Akkermansia and Bifidobacteria but enhanced the lipopolysaccharides level in the serum, which promoted the adipogenesis process by causing dysregulation in the endocannabinoid receptors. Consumption of meat protein with high-fat-induced adiposity, visceral obesity, and dyslipidemia reduced the thermogenesis and had a distinctive effect on the mitochondrial biogenesis compared with casein protein.

Seabuckthorn (Hippophaë rhamnoides) Freeze-Dried Powder Protects against High-Fat Diet-Induced Obesity, Lipid Metabolism Disorders by Modulating the Gut Microbiota of Mice

This study aimed to investigate the beneficial effects of seabuckthorn freeze-dried powder on high-fat diet-induced obesity and related lipid metabolism disorders, and further explored if this improvement is associated with gut microbiota. Results showed that seabuckthorn freeze-dried powder administration decreased body weight, Lee’s index, adipose tissue weight, liver weight, and serum lipid levels. Moreover, treatment with seabuckthorn freeze-dried powder effectively reduced fat accumulation by modulating the relative expression of genes involved in lipid metabolism through down-regulation of encoding lipogenic and store genes, including SREBP-1c, PPAR-γ, ACC, and SCD1, and up-regulation of regulating genes of fatty acid oxidation, including HSL, CPT-1, and ACOX. Especially, seabuckthorn freeze-dried powder regulated the composition of gut microbiota, such as increasing the ratio of Firmicutes/Bacteroidetes, decreasing relative abundance of harmful bacteria (Desulfovibrio), and increasing relative abundance of beneficial bacteria (Akkermansia and Bacteroides). The changes of beneficial bacteria had a positive correlation with genes encoding lipolysis and a negative correlation with genes encoding lipid lipogenesis and store. The harmful bacteria were just the opposite. Besides, changes in gut microbiota had an obvious effect in the secretion of main metabolites—short-chain fatty acids (SCFAs), especially propionic acid. Thus, our results indicated that the seabuckthorn freeze-dried powder could ameliorate high-fat diet-induced obesity and obesity-associated lipid metabolism disorders by changing the composition and structure of gut microbiota.

The probiotic Lactobacillus fermentum 296 attenuates cardiometabolic disorders in high fat diet-treated rats

BACKGROUND AND AIM

High-fat (HF) diet consumption has been associated with gut dysbiosis and increased risk of dyslipidemia, type 2 diabetes mellitus and hypertension. Probiotic administration has been suggested as a safe therapeutic strategy for the treatment of cardiometabolic disorders. This study was designed to assess the effects of probiotic Lactobacillus (L.) fermentum 296, a fruit-derived bacteria strain, against cardiometabolic disorders induced by HF diet.

METHODS AND RESULTS

Male Wistar rats were divided into control diet (CTL); HF diet; and HF diet treated with Lactobacillus fermentum 296 (HF + Lf 296). The L. fermentum 296 strain at 1 × 10⁹ colony forming units (CFU)/ml were daily administered by oral gavage for 4 weeks. The results showed that rats fed with HF diet displayed insulin resistance, reduced Lactobacillus spp. counts in feces, serum lipids, and oxidative profile. Rats fed on HF diet also demonstrated augmented blood pressure associated with sympathetic hyperactivity and impaired baroreflex control. The administration of L. fermentum 296 for 4 weeks recovered fecal Lactobacillus sp. counts and alleviated hyperlipidemia, sympathetic hyperactivity, and reduced systolic blood pressure in HF rats without affecting baroreflex sensibility.

CONCLUSION

Our results suggest the ability of L. fermentum 296 improve biochemical and cardiovascular parameters altered in cardiometabolic disorders.

Effect of inactivated Bifidobacterium longum intake on obese diabetes model mice (TSOD)

Obesity and diabetes have been increasing at an alarming rate worldwide. Studies have shown the futility of chemical drugs in the treatment of obesity and diabetes. Bifidobacterium longum (BL), a common member of the gut microbiota throughout the human lifespan, has been widely reported to play a role in host health and disease. Here, we evaluated the effects of inactivated cells of BL (IBL) on obesity and blood glucose levels in TSOD mice by administering IBL orally for 5 weeks. The treated mice showed a significant decrease of body weight gain, adipose tissue mass and blood glucose levels, as well as a significant reduction in blood glucose during an oral glucose tolerance test. The treatment also resulted in reduced levels of cholesterol, triglycerides, and NEFA. Moreover, serum and urine analysis showed low creatinine levels in IBL-treated mice. These data demonstrate that IBL may have the potential to prevent obesity and diabetes.

Type 1 diabetes is associated with an increase in cholesterol absorption markers but a decrease in cholesterol synthesis markers in a young adult population

BACKGROUND

To optimize treatment and prevent cardiovascular disease in subjects with type 1 diabetes, it is important to determine how cholesterol metabolism changes with type 1 diabetes.

OBJECTIVE

The objective of the study was to compare plasma levels of campesterol and β-sitosterol, markers of cholesterol absorption, as well as lathosterol, a marker of cholesterol synthesis, in youth with and without type 1 diabetes.

METHODS

Serum samples were obtained from adolescent subjects with type 1 diabetes (n = 175, mean age 15.2 years, mean duration of diabetes 8.2 years) and without diabetes (n = 74, mean age 15.4 years). Campesterol, β-sitosterol, and lathosterol, were measured using targeted liquid chromatography tandem mass spectrometry, compared between groups, and correlated with the available cardiometabolic variables.

RESULTS

Campesterol and β-sitosterol levels were 30% higher in subjects with type 1 diabetes and positively correlated with hemoglobin A1c levels. In contrast, lathosterol levels were 20% lower in subjects with type 1 diabetes and positively correlated with triglycerides, body mass index, and systolic blood pressure.

CONCLUSION

Plasma markers suggest that cholesterol absorption is increased, whereas cholesterol synthesis is decreased in adolescent subjects with type 1 diabetes. Further studies to address the impact of these changes on the relative efficacy of cholesterol absorption and synthesis inhibitors in subjects with type 1 diabetes are urgently needed.

Xiexin Tang ameliorates dyslipidemia in high-fat diet-induced obese rats via elevating gut microbiota-derived short chain fatty acids production and adjusting energy metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional herbal medicine has been taken as a new and effective approach to treat many chronic diseases. Xiexin Tang (XXT), a compound recipe composed of Dahuang (Rheum palmatum L.), Huangqin (Scutellaria baicalensis Georgi) and Huanglian (Coptis chinensis Franch.), has been reported to have hypoglycemic and hypolipidemic effects, but its mechanism remains unclear. Our previous study found that Xiexin Tang markedly ameliorated the composition of the gut microbiota, especially for some short chain fatty acids (SCFAs) producing bacteria, and then notably increased SCFAs production. However, the mechanism of XXT on the fermentation of gut bacteria and further improvement of obesity is not yet clear.

AIM OF THE STUDY

This study aimed to unravel the molecular mechanism of XXT on the amelioration of obesity.

MATERIALS AND METHODS

Here, high-fat diet-induced obese rat model was established to investigate the intervention efficacy following oral administration of XXT. Additionally, the expressions of key enzymes of gut microbe-derived SCFAs biosynthesis and key targets in the signaling pathway of energy metabolism were investigated by ELISA and qPCR analysis.

RESULTS

Results showed that XXT could notably correct lipid metabolism disorders, alleviate systematic inflammation, improve insulin sensitivity and reduce fat accumulation. Additionally, XXT could increase gut microbiota-derived SCFAs-producing capacity by enhancing mRNA levels and activities of SCFA-synthetic key enzymes such as acetate kinase (ACK), methylmalonyl-CoA decarboxylase (MMD), butyryl-CoA: acetate CoA transferase (BUT) and butyrate kinase (BUK), which markedly decreased the adenosine triphosphate (ATP) contents, elevated adenosine diphosphate (ADP) and adenosine monophosphate (AMP) levels and further lowered the energy charge (EC) in obese rats via activating peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)/uncoupling protein-2 (UCP-2) signaling pathway. What's more, XXT could notably ameliorate dyslipidemia via increasing the gene expression of 5'-AMP-activated protein kinase (AMPK) and blocking mammalian target of rapamycin (mTOR) signaling pathway.

CONCLUSIONS

Taken together, our data provided a novel insight into the role of XXT in losing weight from energy metabolism regulation, which unraveled the molecular mechanism of XXT on the alleviation of dyslipidemia and fat heterotopic accumulation. The study provided useful information for XXT in clinical application to treat obesity.

Pectin reduces environmental pollutant-induced obesity in mice through regulating gut microbiota: A case study of p,p'-DDE

BACKGROUND

The prevalence of obesity has raised global concerns. Environmental pollutants are one of the main causes of obesity. Many studies have demonstrated that dietary fiber could reduce obesity induced by high-fat diets, but whether environmental pollutant-induced obesity can be reversed is still unknown.

OBJECTIVES

This study aimed to investigate the effects of pectin on obesity induced by a typical environmental pollutant p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and explore the underlying mechanism by which pectin reversed p,p'-DDE-induced obesity.

METHODS

p,p'-DDE was used to induce obesity in C57BL/6J mice and pectin was supplied during and after cessation of p,p'-DDE exposure. Body and fat weight gain, plasma lipid profile and insulin resistance of mice were assessed. Gut microbiota composition and the levels of short-chain fatty acids (SCFAs) as well as the receptor proteins and hormones in the SCFAs-related signaling pathway were analyzed. Moreover, p,p'-DDE levels in various tissues of mice were detected.

RESULTS

Pectin supplementation reversed body and fat weight gain, dyslipidemia, hyperglycemia and insulin resistance in p,p'-DDE-exposed mice. Furthermore, pectin apparently altered the p,p'-DDE-induced microbial composition and then promoted the levels of SCFAs in colonic feces as well as the expression of G-protein coupled receptors and the concentration of hormone peptide YY (PYY) and glucagon like peptide-1 (GLP-1). Pectin treatment also significantly reduced p,p'-DDE accumulation in mice tissues during p,p'-DDE exposure but did not change p,p'-DDE metabolism after termination of p,p'-DDE exposure.

CONCLUSIONS

Pectin had a good effect on reducing p,p'-DDE-induced obesity through regulating gut microbiota and provided a potential strategy for the treatment of environmental pollutant-caused health problems.

Probiotic Ingestion, Obesity, and Metabolic-Related Disorders: Results from NHANES, 1999-2014

Gut microbiota dysbiosis has been recognized as having key importance in obesity- and metabolic-related diseases. Although there is increasing evidence of the potential benefits induced by probiotics in metabolic disturbances, there is a lack of large cross-sectional studies to assess population-based prevalence of probiotic intake and metabolic diseases. Our aim was to evaluate the association of probiotic ingestion with obesity, type 2 diabetes, hypertension, and dyslipidemia. A cross-sectional study was designed using data from the National Health and Nutrition Examination Survey (NHANES), 1999–2014. Probiotic ingestion was considered when a subject reported consumption of yogurt or a probiotic supplement during the 24-h dietary recall or during the Dietary Supplement Use 30-Day questionnaire. We included 38,802 adults and 13.1% reported probiotic ingestion. The prevalence of obesity and hypertension was lower in the probiotic group (obesity-adjusted Odds Ratio (OR): 0.84, 95% CI 0.76–0.92, p < 0.001; hypertension-adjusted OR: 0.79, 95% CI 0.71–0.88, p < 0.001). Accordingly, even after analytic adjustments, body mass index (BMI) was significantly lower in the probiotic group, as were systolic and diastolic blood pressure and triglycerides; high-density lipoprotein (HDL) was significantly higher in the probiotic group for the adjusted model. In this large-scale study, ingestion of probiotic supplements or yogurt was associated with a lower prevalence of obesity and hypertension.

High-Glucose or -Fructose Diet Cause Changes of the Gut Microbiota and Metabolic Disorders in Mice without Body Weight Change

High fat diet-induced changes in gut microbiota have been linked to intestinal permeability and metabolic endotoxemia, which is related to metabolic disorders. However, the influence of a high-glucose (HGD) or high-fructose (HFrD) diet on gut microbiota is largely unknown. We performed changes of gut microbiota in HGD- or HFrD-fed C57BL/6J mice by 16S rRNA analysis. Gut microbiota-derived endotoxin-induced metabolic disorders were evaluated by glucose and insulin tolerance test, gut permeability, Western blot and histological analysis. We found that the HGD and HFrD groups had comparatively higher blood glucose and endotoxin levels, fat mass, dyslipidemia, and glucose intolerance without changes in bodyweight. The HGD- and HFrD-fed mice lost gut microbial diversity, characterized by a lower proportion of Bacteroidetes and a markedly increased proportion of Proteobacteria. Moreover, the HGD and HFrD groups had increased gut permeability due to alterations to the tight junction proteins caused by gut inflammation. Hepatic inflammation and lipid accumulation were also markedly increased in the HGD and HFrD groups. High levels of glucose or fructose in the diet regulate the gut microbiota and increase intestinal permeability, which precedes the development of metabolic endotoxemia, inflammation, and lipid accumulation, ultimately leading to hepatic steatosis and normal-weight obesity.

Tributyltin exposure induces gut microbiome dysbiosis with increased body weight gain and dyslipidemia in mice

Gut microbiome dysbiosis plays a profound role in the pathogenesis of obesity and tributyltin (TBT) has been found as an environmental obesogen. However, whether TBT could disturb gut microbiome and the relationship between obesity induced by TBT exposure and alteration in gut microbiota are still unknown. In order to assess the association between them, mice were exposed to TBTCl (50 μg kg^-1) once every three days from postnatal days (PNDs) 24 to 54. The results demonstrated that TBT exposure resulted in increased body weight gain, lager visceral fat accumulation and dyslipidemia in male mice on PND 84. Correspondingly, 16S rRNA gene sequencing revealed that TBT treatment decreased gut microbial species and perturbed the microbiome composition in mice. Furthermore, Pearson's corelation coefficient analysis showed a significantly negative correlation between the body weight and the alpha diversity of gut microbiome. These results suggested that TBT exposure could induce gut microbiome dysbiosis in mice, which might contribute to the obesity pathogenesis.

Aberrant intestinal microbiota in individuals with prediabetes

AIMS/HYPOTHESIS

Individuals with type 2 diabetes have aberrant intestinal microbiota. However, recent studies suggest that metformin alters the composition and functional potential of gut microbiota, thereby interfering with the diabetes-related microbial signatures. We tested whether specific gut microbiota profiles are associated with prediabetes (defined as fasting plasma glucose of 6.1-7.0 mmol/l or HbA_1c of 42-48 mmol/mol [6.0-6.5%]) and a range of clinical biomarkers of poor metabolic health.

METHODS

In the present case-control study, we analysed the gut microbiota of 134 Danish adults with prediabetes, overweight, insulin resistance, dyslipidaemia and low-grade inflammation and 134 age- and sex-matched individuals with normal glucose regulation.

RESULTS

We found that five bacterial genera and 36 operational taxonomic units (OTUs) were differentially abundant between individuals with prediabetes and those with normal glucose regulation. At the genus level, the abundance of Clostridium was decreased (mean log₂ fold change -0.64 (SEM 0.23), p _adj  = 0.0497), whereas the abundances of Dorea, [Ruminococcus], Sutterella and Streptococcus were increased (mean log₂ fold change 0.51 (SEM 0.12), p _adj  = 5 × 10^-4; 0.51 (SEM 0.11), p _adj  = 1 × 10^-4; 0.60 (SEM 0.21), p _adj  = 0.0497; and 0.92 (SEM 0.21), p _adj  = 4 × 10^-4, respectively). The two OTUs that differed the most were a member of the order Clostridiales (OTU 146564) and Akkermansia muciniphila, which both displayed lower abundance among individuals with prediabetes (mean log₂ fold change -1.74 (SEM 0.41), p _adj  = 2 × 10^-3 and -1.65 (SEM 0.34), p _adj  = 4 × 10^-4, respectively). Faecal transfer from donors with prediabetes or screen-detected, drug-naive type 2 diabetes to germfree Swiss Webster or conventional C57BL/6 J mice did not induce impaired glucose regulation in recipient mice.

CONCLUSIONS/INTERPRETATION

Collectively, our data show that individuals with prediabetes have aberrant intestinal microbiota characterised by a decreased abundance of the genus Clostridium and the mucin-degrading bacterium A. muciniphila. Our findings are comparable to observations in overt chronic diseases characterised by low-grade inflammation.

Role of Helicobacter pylori and interleukin 6 -174 gene polymorphism in dyslipidemia: a case-control study

OBJECTIVE

To assess the role of Helicobacter pylori infection and interleukin 6 polymorphism -174 (rs1800795) in dyslipidemia.

DESIGN

Case-control study comparing serum lipids between H. pylori positive and negative patients and controlling for IL-6 -174 polymorphism, age, sex and smoking.

SETTING

3 hospitals performing outpatient endoscopies in the city of Oulu, Finland.

PARTICIPANTS

199 adult patients with dyspepsia symptoms fulfilling Rome criteria originating from ethnically Finnish population. Patients with an immunosuppressive disorder or malignant disease, treated H. pylori infection, immunosuppressive or anticoagulant medication, previous gastric surgery or ongoing antibiotic treatment were excluded.

PRIMARY OUTCOME MEASURES

Association of H. pylori infection and serum lipid concentrations in the whole group or in genotype-based subgroups. The associations between peptic ulcer, gastric mucosal inflammation and serum lipid concentrations were assessed as secondary outcomes.

RESULTS

The median high-density lipoprotein (HDL) serum concentration was significantly lower in the H. pylori positive group (0.81 mmol/L) than in the negative group (0.95 mmol/L; p<0.001). In the genotype subgroup analyses, a similar association between H. pylori infection and HDL serum levels was seen within the IL-6 -174 CC genotype group (HDL 0.72 vs 1.06 mmol/L, respectively; p<0.001), but no significant associations were seen in the GC or GG genotype groups. Additionally, patients with peptic ulcer demonstrated lower HDL levels (0.75 mmol/L) than H. pylori positive patients without ulcer (0.86 mmol/L; p=0.010).

CONCLUSIONS

H. pylori infection associated significantly with low serum levels of HDL in the IL-6 -174 CC genotype patients but not in the other genotypes. This suggests that the association between H. pylori infection and serum HDL could be transmitted through IL-6. We suggest that the role of IL-6 genotype should also be studied in relation to other associations between gastrointestinal microbiome and cardiovascular risk factors.

Metabolic consequences of Helicobacter pylori infection and eradication

Helicobacter pylori (H. pylori) is still the most prevalent infection of the world. Colonization of the stomach by this agent will invariably induce chronic gastritis which is a low-grade inflammatory state leading to local complications (peptic ulcer, gastric cancer, lymphoma) and remote manifestations. While H. pylori does not enter circulation, these extragastric manifestations are probably mediated by the cytokines and acute phase proteins produced by the inflammed mucosa. The epidemiologic link between the H. pylori infection and metabolic changes is inconstant and controversial. Growth delay was described mainly in low-income regions with high prevalence of the infection, where probably other nutritional and social factors contribute to it. The timely eradication of the infection will lead to a more healthy development of the young population, along with preventing peptic ulcers and gastric cancer An increase of total, low density lipoprotein and high density liporotein cholesterol levels in some infected people creates an atherogenic lipid profile which could promote atherosclerosis with its complications, myocardial infarction, stroke and peripheral vascular disease. Well designed and adequately powered long-term studies are required to see whether eradication of the infection will prevent these conditions. In case of glucose metabolism, the most consistent association was found between H. pylori and insulin resistance: again, proof that eradication prevents this common metabolic disturbance is expected. The results of eradication with standard regimens in diabetics are significantly worse than in non-diabetic patients, thus, more active regimens must be found to obtain better results. Successful eradication itself led to an increase of body mass index and cholesterol levels in some populations, while in others no such changes were encountered. Uncertainities of the metabolic consequences of H. pylori infection must be clarified in the future.

[Hygienic causal aspects of chronic biogeochemical stress]

Chronic biogeochemical stress results in enteric dysbiosis and is one of the active triggers, that cause deviations of integrative homeostatic parameters, and responsible for the high prevalence of atherosclerotic changes, including myocardial infarction, among the population of the silicon biogeochemical province of the Chuvash Republic, which is associated with the body's nonspecific adaptive reactions.

[Advisability of using probiotics in the treatment of atherogenic dyslipidemia]

One of the main components of the metabolic syndrome is a non-alcoholic fatty liver disease (NAFLD). Currently, NAFLD is recognized as one of the main factors for cardiovascular disease because cholesterol synthesis is carried out mainly in the liver. In connection with this selection of lipid-lowering therapy, which has a known hepatotoxic effect, is a challenge. In the pathogenesis of NAFLD important role played by the violation of the colon microflora and, consequently, elevated levels of metabolic products of microorganisms (short chain fatty acids, endotoxin, nitric oxide), which must also be considered in the treatment of atherogenic dyslipidemia. In patients with NAFLD and atherogenic dyslipidemia appointment of combination therapy of statins and probiotics are more effective in lowering cholesterol and products of metabolism of intestinal microflora compared with monotherapy.

[Intestinal dysbiosis and atherogenic dyslipidemia]

Numerous studies in recent years had proved pathogenetic correlation of the intestinal ecological community, not only with diseases of the gastrointestinal tract but also with diseases such as atherosclerosis and hypertension, urolithiasis and pyelonephritis, gallstones and hepatitis. In its role in maintaining homeostasis an intestinal microflora isn't inferior to any other vital organs. All this allowed to distinguish it as an independent body. Recently, as one of the most important factors for the development of dyslipidemia scientists consider breaking the functional state of the liver, as well as changes in blood lipid spectrum and disturbance of cholesterol metabolism begins at the level of the hepatocyte. However, in 2001, Carneiro de Moura proposed a theory of violation of the microbial community in the colon as one of the ways to lipid metabolism. By reducing the detoxification function of intestinal microflora associated with Microecological disorders of various origins, the first "hit" is to the host liver--is on one side. On the other--the vast majority of microorganisms are characterized by a pronounced ability of bile acids deconjugation, and therefore the increased reproduction in the ileum of bacteria (especially anaerobic, with enhanced activity against deconjugation activity to related bile acids) and the formation of toxic endogenous bile salts, acids are important prerequisites for the occurrence of violations of all functions of the liver, including the activities of Kupffer cells and the whole system of mononuclear macrophages. In this regard, the formation and progression of dyslipidemia, regardless of the target organ must be closely linked with the digestive tract by micro. Schematically it can be represented as follows: violation of microecology intestine --> accumulation of endotoxin in the gut --> entry of endotoxins in portal vein to the liver --> RES of liver cell damage --> strengthening the pathological effects of toxicants other (non-microbial) origin --> dysfunction of hepatocytes --> dislipoproteidemiya.

Periodontal infection and dyslipidemia in type 2 diabetics: association with increased HMG-CoA reductase expression

Recent studies have suggested that the periodontal disease, chronic sub-clinical inflammation, is associated with atherosclerosis, although "cause or effect" relationship is still unclear. The aim of this study was to assess the association between the degree of periodontal infection and lipid profiles in diabetic subjects. Additionally, the association of such sub-clinical inflammation with HMG-CoA reductase gene expression was evaluated. One hundred and thirty-one non-obese relatively well-controlled Japanese type 2 diabetic patients were enrolled for the study. Although no significant association was observed between serum triglycerides, HLD-cholesterol and antibody titer to Porphyromonas gingivalis (Pg), the most predominant periodontal pathogen in adults, LDL-cholesterol was significantly associated with antibody titer to Pg. Concomitantly, the same works out to be true for total cholesterol. To understand the possible mechanisms underlying this association, we evaluated 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase gene expression in cultured HepG2 cells stimulated by either bacterial lipopolysaccharide (LPS) or inflammatory cytokines. Although Pg and E. coli LPS had no effect on HMG-CoA reductase gene expression, both tumor necrosis factor-alpha and interleukin-6 (IL-6), especially IL-6 at low concentration, markedly up-regulated HMG-CoA reductase gene expression. It can be concluded that Pg infection is associated with increased LDL-cholesterol in diabetic subjects, which may be accompanied by increased cholesterol synthesis by inflammatory cytokines.